I completed my first tandem jump this summer and realized that I want to get certified next summer (i live in new england where the dropzones close for the winter). However, my friend just asked me to go skydiving with him for his 18th birthday in October. Should I spend the money on another Tandem or should I invest and do my first AFF jump? Or would it be better to wait till next summer and do all of my AFF jumps at the same time?